﻿using Photonware.RestUI.Core;
using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace RestUI.Utils
{

    public class HttpProcessor {
        public TcpClient socket;        
        public HttpServer srv;

        private Stream inputStream;
        public StreamWriter outputStream;

        public String http_method;
        public String http_url;
        public String http_protocol_versionstring;
        public Hashtable httpHeaders = new Hashtable();


        private static int MAX_POST_SIZE = 10 * 1024 * 1024; // 10MB

        public HttpProcessor(TcpClient s, HttpServer srv) {
            this.socket = s;
            this.srv = srv;                   
        }
        

        private string streamReadLine(Stream inputStream) {
            int next_char;
            string data = "";
            while (true) {
                next_char = inputStream.ReadByte();
                if (next_char == '\n') { break; }
                if (next_char == '\r') { continue; }
                if (next_char == -1) { Thread.Sleep(1); continue; };
                data += Convert.ToChar(next_char);
            }            
            return data;
        }
        public void process()
        {

            try
            {
                using (inputStream = new BufferedStream(socket.GetStream()))
                {
                    using (outputStream = new StreamWriter(new BufferedStream(socket.GetStream()), Encoding.UTF8))
                    {

                        parseRequest();
                        readHeaders();
                        if (http_method.Equals("GET"))
                        {
                            handleGETRequest();
                        }
                        //else if (http_method.Equals("POST"))
                        //{
                        //    handlePOSTRequest();
                        // }

                        outputStream.Flush();

                    }
                }
            }
            catch (Exception e)
            {
                Console.WriteLine("Exception: " + e.ToString());
                writeFailure();
            }
            finally
            {
                try
                {
                    socket.Close();
                }
                catch { }
            }
        }

        public void parseRequest() {
            String request = streamReadLine(inputStream);
            string[] tokens = request.Split(' ');
            if (tokens.Length != 3) {
                throw new Exception("invalid http request line");
            }
            http_method = tokens[0].ToUpper();
            http_url = tokens[1];
            http_protocol_versionstring = tokens[2];

            //Console.WriteLine("starting: " + request);
        }

        public void readHeaders() {
            //Console.WriteLine("readHeaders()");
            String line;
            while ((line = streamReadLine(inputStream)) != null) {
                if (line.Equals("")) {
                    //Console.WriteLine("got headers");
                    return;
                }
                
                int separator = line.IndexOf(':');
                if (separator == -1) {
                    throw new Exception("invalid http header line: " + line);
                }
                String name = line.Substring(0, separator);
                int pos = separator + 1;
                while ((pos < line.Length) && (line[pos] == ' ')) {
                    pos++; // strip any spaces
                }
                    
                string value = line.Substring(pos, line.Length - pos);
                //Console.WriteLine("header: {0}:{1}",name,value);
                httpHeaders[name] = value;
            }
        }

        public void handleGETRequest() {
            srv.handleGETRequest(this);
        }

        private const int BUF_SIZE = 4096;
        public void handlePOSTRequest() {
            // this post data processing just reads everything into a memory stream.
            // this is fine for smallish things, but for large stuff we should really
            // hand an input stream to the request processor. However, the input stream 
            // we hand him needs to let him see the "end of the stream" at this content 
            // length, because otherwise he won't know when he's seen it all! 

            //Console.WriteLine("get post data start");
            int content_len = 0;
            MemoryStream ms = new MemoryStream();
            if (this.httpHeaders.ContainsKey("Content-Length")) {
                 content_len = Convert.ToInt32(this.httpHeaders["Content-Length"]);
                 if (content_len > MAX_POST_SIZE) {
                     throw new Exception(
                         String.Format("POST Content-Length({0}) too big for this simple server",
                           content_len));
                 }
                 byte[] buf = new byte[BUF_SIZE];              
                 int to_read = content_len;
                 while (to_read > 0) {  
                     Console.WriteLine("starting Read, to_read={0}",to_read);

                     int numread = this.inputStream.Read(buf, 0, Math.Min(BUF_SIZE, to_read));
                     Console.WriteLine("read finished, numread={0}", numread);
                     if (numread == 0) {
                         if (to_read == 0) {
                             break;
                         } else {
                             throw new Exception("client disconnected during post");
                         }
                     }
                     to_read -= numread;
                     ms.Write(buf, 0, numread);
                 }
                 ms.Seek(0, SeekOrigin.Begin);
            }
            Console.WriteLine("get post data end");
            srv.handlePOSTRequest(this, new StreamReader(ms));

        }

        public void writeSuccess(string content_type="text/html") {
            outputStream.WriteLine("HTTP/1.0 200 OK");            
            outputStream.WriteLine("Content-Type: " + content_type);
            outputStream.WriteLine("Connection: close");
            outputStream.WriteLine("");
        }

        public void writeFailure() {
            outputStream.WriteLine("HTTP/1.0 404 File not found");
            outputStream.WriteLine("Connection: close");
            outputStream.WriteLine("");
        }
    }

    public abstract class HttpServer {

        protected int port;
        protected TcpListener listener;
        protected bool is_active = true;

        public int Port { get { return port; } }
       
        public HttpServer(int port) {
            this.port = port;
        }

        public void listen() {
            try
            {
                listener = new TcpListener(IPAddress.Parse("0.0.0.0"), port);
                listener.Start();
                while (is_active)
                {
                    TcpClient s = listener.AcceptTcpClient();
                    HttpProcessor processor = new HttpProcessor(s, this);
                    Thread thread = new Thread(new ThreadStart(processor.process));
                    thread.Start();
                    Thread.Sleep(1);
                }
            }
            catch { }
        }

        public abstract void handleGETRequest(HttpProcessor p);
        public abstract void handlePOSTRequest(HttpProcessor p, StreamReader inputData);
    }

    public class SimpleHttpServer : HttpServer {

        private List<UserCase> usercases = null;
        public string Url { get; private set; }
        public SimpleHttpServer(List<UserCase> usercases, int port)
            : base(port) {
                this.usercases = usercases;
        }

        public void Start()
        {
            if (this.port == 0)
            {

                TcpListener tcp = new TcpListener(IPAddress.Parse("0.0.0.0"), 0);
                try
                {
                    tcp.Start();
                    port = (tcp.LocalEndpoint as IPEndPoint).Port;
                }
                catch { }
                finally
                {
                    try
                    {
                        tcp.Stop();
                    }
                    catch { }
                }

                this.port = port;
            }

            Task task = new Task(() =>
            {
                this.listen();
            });
            task.Start();
            this.Url = string.Format("http://{0}:{1}/{2}", GetLocalIP(), this.port, "");// Guid.NewGuid().ToString().Split('-')[0]);
            Console.WriteLine("Listening on: " + this.Url);
        }

        public void Stop()
        {
            this.is_active = false;
            try
            {
                this.listener.Stop();
            }
            catch { }
        }

        private string GetLocalIP()
        {
            string _IP = null;

            // Resolves a host name or IP address to an IPHostEntry instance.
            // IPHostEntry - Provides a container class for Internet host address information. 
            System.Net.IPHostEntry _IPHostEntry = System.Net.Dns.GetHostEntry(System.Net.Dns.GetHostName());

            // IPAddress class contains the address of a computer on an IP network. 
            foreach (System.Net.IPAddress _IPAddress in _IPHostEntry.AddressList)
            {
                // InterNetwork indicates that an IP version 4 address is expected 
                // when a Socket connects to an endpoint
                if (_IPAddress.AddressFamily.ToString() == "InterNetwork")
                {
                    _IP = _IPAddress.ToString();
                    break;
                }
            }
            return _IP;
        }

        public override void handleGETRequest (HttpProcessor p)
		{
            StringBuilder sb = new StringBuilder();
            foreach (UserCase uc in usercases)
            {
                sb.AppendLine(uc.ToJsonString());
            }

            p.writeSuccess();
            p.outputStream.Write(sb.ToString());
            p.outputStream.BaseStream.Flush();
        }

        public override void handlePOSTRequest(HttpProcessor p, StreamReader inputData) {
            Console.WriteLine("POST request: {0}", p.http_url);
            string data = inputData.ReadToEnd();

            p.writeSuccess();
            p.outputStream.WriteLine("<html><body><h1>test server</h1>");
            p.outputStream.WriteLine("<a href=/test>return</a><p>");
            p.outputStream.WriteLine("postbody: <pre>{0}</pre>", data);
            

        }
    }

}



